This invention relates generally to airflow in turbofan engines, and more specifically to regulating the airflow through the fan duct area.
At least one known turbofan engine assembly includes a fan assembly and a core gas turbine engine enclosed in an annular core cowl. Additionally, a fan nacelle surrounds a portion of the core gas turbine engine. The core cowl and fan nacelle generally form a fan nozzle duct area (A18). While operating the turbofan engine assembly, a portion of the air flowing from the fan assembly flows through the core gas turbine engine and another portion of the air flows through the fan nozzle duct area.
In some turbofan engine assemblies, the fan nozzle duct area can be manipulated in order to alter engine performance. For example, some turbofan engines utilize a translating core cowl as a thrust reverser without blocker doors by essentially reducing the fan nozzle duct area.
Additional methods and assemblies are needed to vary the fan nozzle duct area to increase cycle performance at take-off and descent portions.